NAME¶
Sub::Util - A selection of utility subroutines for subs and CODE references
SYNOPSIS¶
use Sub::Util qw( prototype set_prototype subname set_subname );
DESCRIPTION¶
"Sub::Util" contains a selection of utility subroutines that are
useful for operating on subs and CODE references.
The rationale for inclusion in this module is that the function performs some
work for which an XS implementation is essential because it cannot be
implemented in Pure Perl, and which is sufficiently-widely used across CPAN
that its popularity warrants inclusion in a core module, which this is.
FUNCTIONS¶
prototype¶
my $proto = prototype( $code )
Since version 1.40.
Returns the prototype of the given $code reference, if it has one, as a string.
This is the same as the "CORE::prototype" operator; it is included
here simply for symmetry and completeness with the other functions.
set_prototype¶
my $code = set_prototype $prototype, $code;
Since version 1.40.
Sets the prototype of the function given by the $code reference, or deletes it
if $prototype is "undef". Returns the $code reference itself.
Caution: This function takes arguments in a different order to the
previous copy of the code from "Scalar::Util". This is to match the
order of "set_subname", and other potential additions in this file.
This order has been chosen as it allows a neat and simple chaining of other
"Sub::Util::set_*" functions as might become available, such as:
my $code =
set_subname name_here =>
set_prototype '&@' =>
set_attribute ':lvalue' =>
sub { ...... };
subname¶
my $name = subname( $code )
Since version 1.40.
Returns the name of the given $code reference, if it has one. Normal named subs
will give a fully-qualified name consisting of the package and the localname
separated by "::". Anonymous code references will give
"__ANON__" as the localname. If a name has been set using
"set_subname", this name will be returned instead.
This function was inspired by "sub_fullname" from Sub::Identify. The
remaining functions that "Sub::Identify" implements can easily be
emulated using regexp operations, such as
sub get_code_info { return (subname $_[0]) =~ m/^(.+)::(.+?)$/ }
sub sub_name { return (get_code_info $_[0])[0] }
sub stash_name { return (get_code_info $_[0])[1] }
Users of Sub::Name beware: This function is
not the same as
"Sub::Name::subname"; it returns the existing name of the sub rather
than changing it. To set or change a name, see instead
"set_subname".
set_subname¶
my $code = set_subname $name, $code;
Since version 1.40.
Sets the name of the function given by the $code reference. Returns the $code
reference itself. If the $name is unqualified, the package of the caller is
used to qualify it.
This is useful for applying names to anonymous CODE references so that stack
traces and similar situations, to give a useful name rather than having the
default of "__ANON__". Note that this name is only used for this
situation; the "set_subname" will not install it into the symbol
table; you will have to do that yourself if required.
However, since the name is not used by perl except as the return value of
"caller", for stack traces or similar, there is no actual
requirement that the name be syntactically valid as a perl function name. This
could be used to attach extra information that could be useful in debugging
stack traces.
This function was copied from "Sub::Name::subname" and renamed to the
naming convention of this module.
AUTHOR¶
The general structure of this module was written by Paul Evans
<leonerd@leonerd.org.uk>.
The XS implementation of "set_subname" was copied from Sub::Name by
Matthijs van Duin <xmath@cpan.org>